I agree with David that the Chateau is well worth a visit. It is also houses the Service historique de la Défense (SHD), home of the French military archives. The reading room is in the Pavillon du Roi, with the Pavillon de la Reine opposite - the Chateau was a royal residence before Louis XIV moved to Versailles. The Pavillon du Roi has a number of large paintings (see for example this from TMP: http://theminiaturespage.com/boards/msg.mv?id=504162 - follow the link in the initial post), and displays of insignia, flags etc, which can be seen even if you are not using the archives.